HCCS | |||||||||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Identifiers | |||||||||||||||||||||||||||||||||||||||||||||||||||
Aliases | HCCS , CCHL, MCOPS7, MLS, LSDMCA1, holocytochrome c synthase | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | OMIM: 300056; MGI: 106911; HomoloGene: 3897; GeneCards: HCCS; OMA:HCCS - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
Wikidata | |||||||||||||||||||||||||||||||||||||||||||||||||||
|
Cytochrome c-type heme lyase is an enzyme that in humans is encoded by the HCCS gene on chromosome X. [5]
The HCCS gene is located on the Xp22 region of chromosome X and encodes a protein that is ~30 kDa in size. The HCCS protein is localized to the inner mitochondrial membrane and is expressed in multiple tissue including prominently in the cardiovascular system and the central nervous system. [6]
The HCCS protein functions as a lyase to covalently attach the heme group to the apoprotein of cytochrome c on the inner mitochondrial membrane of the mitochondrion. [7] The heme group is required for cytochrome c to transport electrons from complex III to complex IV of the electron transport chain during respiration. Heme attachment to cytochrome c takes place in the intermembrane space and requires conserved heme-interacting residues on HCCS on one of the two heme-binding domains on HCCS, including His154. [8] The HCCS protein may function to regulate mitochondrial lipid and total mitochondrial mass in response to mitochondrial dysfunctions. [9]
Mutations in the HCCS gene cause microphthalmia with linear skin defects (MLS) syndrome, [10] also known as MIDAS syndrome, microphthalmia, syndromic 7 (MCOPS7), or microphthalmia, dermal aplasia, and sclerocornea. [11] [12] MLS is a rare X-linked dominant male-lethal disease characterized by unilateral or bilateral microphthalmia and linear skin defects in affected females, and in utero lethality for affected males. [11]